1.   Severe lead poisoning is a cause of intellectual impairment.

2.   The fundamental issue in the current debate is whether environmental lead causes intellectual impairment or behavioural disturbances in children.

3.   The crucial cognitive effects of damage are due to both general intellectual impairment and specific reading retardation.

4.   Because a clamp is placed across the aorta as part of the operation, bits of plaque can break off during bypass operations to cause strokes and intellectual impairment.